|Year : 2002 | Volume
| Issue : 2 | Page : 131-135
Helical CT angiography : A single imaging modality to evaluate a live renal donor
Waheed Zaman, Anant Kumar, Rajshekhar Gupta, Subodh Das, Anil Mandhani, Aneesh Srivastava, Archana Gupta
Department of Urology & Radiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
Department of Urology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow - 226 014
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Introduction: Traditionally live related renal donors are evaluated with intravenous urography and renal arteriography. The computerized tomographic angiography (CTA) can offer a less invasive alternative to demonstrate the necessary anatomical and functional information. The present study evaluates the accuracy of helical CTA in depicting renal vascular and parenchymal anatomy in live renal donors.
Patients and Methods: During March 1999 to March 2000 all live donors were evaluated with ultrasound abdomen (USG), intravenous urography (IVU) and helical CT (Picker PQ 5000, Picker Intl. USA). Renal arterial and venous anatomy was documented prospectively by a radiologist, which was correlated with the operative findings. Sensitivity, specificity and accuracy of CTA in depicting the renal vascular anatomy were assessed.
Results: Of 120 live donors evaluated, overall concordance between CT angiography and operative findings in delineating the arterial anatomy was found in 110 (91.6%) and venous in 116 (96.6%) donors. The sensitivity, specificity, and accuracy of CTA in depicting arterial anatomy was 91.6%, 98.2% & 91.6% and for venous anatomy was 96.7%, 90.0% and 97.0% respectively. We could not gather any additional information by performing intravenous urography.
Conclusions: Helical CT angiography, which is highly specific for arterial and venous anatomy as well as other anatomical and functional details, can become the single imaging modality for preoperative assessment of potential donors in place of conventional angiography and IVU. CTA, being minimally invasive and cost effective, is well accepted by a normal healthy donor
Keywords: Live Renal Donors; Helical CT Angiography
|How to cite this article:|
Zaman W, Kumar A, Gupta R, Das S, Mandhani A, Srivastava A, Gupta A. Helical CT angiography : A single imaging modality to evaluate a live renal donor. Indian J Urol 2002;18:131-5
|How to cite this URL:|
Zaman W, Kumar A, Gupta R, Das S, Mandhani A, Srivastava A, Gupta A. Helical CT angiography : A single imaging modality to evaluate a live renal donor. Indian J Urol [serial online] 2002 [cited 2020 Jul 12];18:131-5. Available from: http://www.indianjurol.com/text.asp?2002/18/2/131/37613
| Introduction|| |
Renal transplant has become the treatment of choice for the end stage renal disease.  Potential live renal donors undergo extensive preoperative evaluation which includes medical history, laboratory testing and radiological imaging. Assessment of renal anatomy is integral to the evaluation of living kidney donors. Ideally, the studies chosen should provide vascular, parenchymal and ureteral anatomy and give us an idea about the renal function. Evaluation of anatomy is essential to ensure that the vascular anatomy is normal or can be adequately reconstructed. Additionally, preoperative decision, such as which kidney to remove, is often based upon the results of imaging studies. ,
Traditionally, imaging has included ultrasound abdomen, renal scan, excretory urography and conventional renal arteriography. Conventional angiography necessitates one day admission and 12 hrs post procedural observation, which causes inconvenience to potential donors and leads to additional costs to the transplant program. ,
Helical CT is highly accurate and specific for the demonstration of renal vascular anatomy. It provides essential anatomical information and can be an alternative to standard urography and ateriography. Helical CT being an out patient procedure reduces cost of imaging and decreases morbidity associated with angiography. ,,,
In this prospective study we evaluate the accuracy of helical CT angiography in depicting bilateral renal vascular, parenchymal and ureteral anatomy as well as the excretory pattern through a single imaging modality to evaluate live renal donors.
| Patients and Methods|| |
The study involved a total of 120 potential kidney donors (M:F 35:85). Mean age of the donors was 41.5±9.2 (19-71) years. Initial clinical and laboratory assessment was done to ensure normal renal function. All live donors were evaluated with ultrasound abdomen (USG), intravenous urography (IVU) and helical CT angiography (CTA). Imaging studies were done on the donors according to a standard CT angiographic protocol, that is early arterial phase scanning (14-20 sec. Delay) & 5 mm 3 dimensional maximum intensity projection. CT was performed on a 4 th generation slip ring technology CT scanner (Picker PQ 5000, Picker Intl. Cleveland, USA).
Renal arterial anatomy was evaluated for the number and location of arteries, accessory arteries, early branching (within 1.5 cm of origin) and arterial stenosis. Venous anomalies, non-vascular abnormalities including parenchymal and collecting system abnormality, calculus and non-renal abnormalities were noted. All images were interpreted by a single radiologist at our institution and reviewed by operating surgeon before harvesting the allograft.
The findings reported on helical CTA were used to select the donor kidney. CTA findings were correlated with the IVU and operative findings and finally the sensitivity, specificity and accuracy of CTA in depicting the renal vascular, parenchymal and ureteral abnormalities were assessed.
| Results|| |
Open donor neprectomy was performed in 104 potential donors, while 16 donors underwent laparoscopic donor nephrectomy. Nephrectomy was performed on the left side in 104 and 16 on the right side in donors, after preoperative imaging showed complex vascular anatomy of the left kidney (3 or more renal artery) in 9 and several small cysts in right kidney in 4 donors.
Multiple renal arteries were present in 5 (4.1%); 2 arteries in 4 and 3 in one donor [Figure - 1]. Early branching of the main renal artery was seen in 7 cases (5.8%). Venous anomalies noted in 7 donors (5.8%), which consisted of retroaortic renal vein in 2 [Figure - 2], multiple veins in 3 and duplication of IVC in 2 cases [Figure - 3]. Similarly non-vascular renal abnormalities were identified in 15 cases (12.5%) [Figure - 4]. Renal calculi were seen in 2 and simple renal cysts were noted in 6 donors. A pelvic kidney was diagnosed via CT angiography (CTA) and harvested by open donor nephrectomy successfully. We could not gather any addition] information by performing intravenous urography. CTA has shown 100% accuracy for non-vascular lesions [Table - 1].
The overall concordance between CTA and preoperative findings in delineating the arterial anatomy was found in 110 cases (91.1%). 7 patients in whom CTA had shown single renal artery were found to have double renal artery preoperatively. In 5 patients CTA had missed a small aberrant renal artery which was detected preoperatively. In 3 patients CTA had revealed suspicious renal artery stenosis at the hilum, but during surgery 2 cases didn't reveal any such abnormality. Renal arterial flow was confirmed on Doppler ultrasound. The sensitivity, specificity and accuracy of CTA in detecting arterial anatomy were 91.6%, 98.2% & 91.6% respectively [Table - 2],[Table - 3].
There were 4 cases of discordance between CTA and surgery in the identification of venous anatomy. In two cases IVC duplication was diagnosed preoperatively, which was subsequently confirmed on surgery, but in one case it was missed. In one of them CT had revealed B/L double renal veins, but preoperatively the patient was found to have single renal vein on left side. In the other patient CT had missed the early branching of the left renal vein. The sensitivity, specificity and accuracy of CTA in delineating the venous anatomy were 96.7%, 90.0% & 97% respectively [Table - 2],[Table - 3].
| Discussion|| |
The success of live renal donor transplantation depends on reliable characterization of renal morphology and function. Renal angiography has long been considered the gold standard for the assessment of renal arterial anatomy.  But, it is invasive in nature and has risk of bleeding and arterial injury to the tune of 1.7%. , It also requires post procedural observation and causes discomfort to the patient. Moreover, arteriography doesn't provide parenchymal or venous anatomy and provides no 3-D image to the operating surgeon. With the development of helical CT scanning and 3-D reconstruction, imaging of arterial and venous anatomy in three dimensions can be obtained. ,,,
In addition to identifying renal vascular and collecting system anatomy, preoperative assessment allows the surgeon to look for vascular plaques and calcification, tumors, cysts and fibrodysplastic disease of the renal artery. Abdominal CT is the gold standard for the evaluation of parenchymal disease in the kidney. CT provides images of renal parenchymal anatomy and therefore identifies cysts and tumors. ,,,,,
The ability to define arterial, venous and renal parenchymas in 3 dimensions is a distinct advantage for planning an operation. The operating surgeon can accurately anticipate early branching and can plan the operative approach by knowing the relationship of artery and vein, thereby decreasing the risk of vessel injury. , It is specially more relevant during laparoscopic live donor nephrectomy.
Various studies comparing renal arterial anatomy image obtained by helical CT and arteriography found agreement in 89-96%. , Our study demonstrated accuracy of CT scanning in defining renal arterial and venous anatomy in 91.6% and 97% respectively. CT angiography (CTA) has been reported as less sensitive for detecting the venous anamolies.  We have found in our study that venous anomalies, such as multiple renal veins, retroaortic vein and circumaortic renal vein were easily identified by helical CT with 3-D reconstruction. Venous opacification and anatomical delineation are better on CT than conventional arteriography.  Preoperative identification of venous anomalies can result in shorter operative time and minimizes morbidity from unexpected vascular injury. 
Helical CTA has also been found to have an edge over urography and conventional arteriography in detecting nonvascular abnormalities such as benign and malignant masses, renal and ureteral calculi. parenchymal scarring and ureteral duplication.  Nonvascular abnormalities were found in 12.5% of donors in our study. In addition, CT enables evaluation of other abdominal and pelvic organs and may identify patients not suitable for kidney donation. Recently few studies have indicated that CT has an accuracy rate sufficient to replace IVU and renal arteriography. , CTA can be performed as a safe outpatient procedure. ,,,,, There is 25% reduction in cost for imaging the potential donor with CTA versus standard renal arteriography and IVU (Rs.4500 vs. 6000).
Helical CTA with 3-D reconstruction has become the standard method of imaging in living donors at our institution. It is simple, accurate, less expensive, convenient, less time consuming and well accepted by the patients.
We believe that CT angiography is the radiological procedure of choice for assessment of renal anatomy in potential living kidney donors and equally safe for graft retrieval. It can replace conventional angiography and intravenous urography for donor assessment. Based on this study, we can recommend ultrasonography as an initial screening modality followed by CTA. This way, we can avoid IVU and conventional angiography and can cut down the cost, hospitalization and morbidity of living renal donors.
| Conclusions|| |
Helical CT angiography (CTA) is highly specific for arterial and venous anatomy as well as other anatomical and functional details and can become the primary imaging modality for preoperative assessment of potential donors in place of IVU and conventional angiography. There is greater patient acceptance and less morbidity associated with non-invasive nature of helical CT. It is also cost effective. It can thus be established as a single imaging modality to evaluate live donors.
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[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4]
[Table - 1], [Table - 2], [Table - 3]